These are all translations from fragments of the tale found in various Irish manuscripts from Trinity College and Royal Irish Academy, compiled together to make a complete narrative. Oiḋe ċloinne Lir has the story in Irish as well as the English translation. Here are a few examples (not comprehensive) of where they can be found, I have tried to link directly to the relevant web page on the site where possible.
Online Books-Full electronic copies of facsimiles of the above books can be found for free. For example The Internet Archive-Old Celtic Romances, Oiḋe ċloinne Lir, Gods and fighting men
Online Booksellers-For example Amazon-Old Celtic Romances, , Gods and fighting men and Abe Books-Old Celtic Romances, Oiḋe ċloinne Lir, Gods and Fighting Men
Book shops-(you may have to order), you could try finding an independent local bookshop in your area